Commercial capi newfields

This adds two (optional) links to the single CAPI DFP component.

Also tweaked the layout so the line length doesn't stretch full width if there isn't a link

Before;
![screen shot 2014-11-13 at 15 49 03](https://cloud.githubusercontent.com/assets/1303616/5031143/da9ddc1c-6b4c-11e4-94ee-2d7ee03d9741.png)

After;
![screen shot 2014-11-13 at 15 49 14](https://cloud.githubusercontent.com/assets/1303616/5031147/e02221ac-6b4c-11e4-8498-567dd989f087.png)

There are some implciits that could make your query string code (a little bit) prettier...

https://github.com/guardian/frontend/blob/master/common/app/implicits/Requests.scala